Vasoactive intestinal peptide (VIP) stimulated bone resorption in mouse calvaria in organ culture. This VIP stimulation was as great as that produced by two other polypeptides, epidermal growth factor and platelet-derived growth factor, which we have previously found to act via a prostaglandin-mediated mechanism. However, unlike these polypeptides, VIP acts to enhance bone resorption via a cyclic AMP-dependent, prostaglandin-independent mechanism. Rabbit, chicken, rat, and dog erythrocytes (109 cells/ml) synthesized i12-HETE when stimulated by the CA2+ ionophore, A-23187. The levels of iHETE were independent of the number of white blood cells and platelets in the erythrocyte suspensions. Two products were resolved by high-pressure liquid chromatography; one product was identified as 12-HETE, and a second product appeared to be a diHETE. Rat basophil leukemia cells (RBL-1), when grown in a monolayer, synthesized from endogenous substrates prostaglandins (PG) E2, F2alpha, I2 (measured as 6-keto-PGF1alpha), 6-sulfidopeptide-containing leukotrienes (SRS), as well as materials that react serologically with anti-12-hydroxyeicosatetraenoic acid. The nonsteroidal anti-inflammatory drugs indomethacin and aspirin inhibited PGE2 synthesis by RBL-1 cells. Indomethacin, when used at higher concentrations, also inhibited iSRS synthesis. Benoxaprofen, also a nonsteroidal anti-inflammatory drug, inhibited both PGE2 and iSRS production, but inhibition of iSRS biosynthesis was three times more effective than inhibition of PGE2 production. Gossypol, BW755c, BHA and NDGA, as well as benoxaprofen, inhibited i12-HETE biosynthesis. Two calcium channel blockers, verapamil and nifedipine, inhibited PGE2, iSRS, and i12-HETE synthesis. The calcium channel blockers inhibited iSRS synthesis 10 times more effectively than PGE2 production. Arachidonic acid metabolites were identified insalivary secretions of rabbits, rats, and humans. These products were also identified in homogenates of rabbit parotid and submaxillary glands. Levels of PGE2, PGE2alpha, serologically active 6-sulfidopeptide-containing leukotrienes, and serologically active HETEs were determined in salivas of healthy volunteers. In all instances, HETEs markedly predominated over all other arachidonic acid metabolites. Levels of three prostaglandins, PGE2, PGF2alpha, and PGI2 (measured a 6-keto-PGE1alpha), serologically active 6-sulfidopeptide-containing leukotrienes, and hydroxyeicosatetraenoic acids also were determined in mixed salivas of eight healthy volunteers at several flow rates. (B)